Plate clamp registering mechanism

ABSTRACT

A rotatable plate-carrying cylinder has a body member with a longitudinal gap in the periphery thereof. A plate clamp member is mounted in the gap and extends along a side surface of the gap and is laterally adjustable in opposite directions from a predetermined plate-receiving position spaced from the side surface of the gap toward and away from the side surface of the gap. A rotatable screw means threadedly engageable with the clamp member is rotatable to provide for movement of the clamp member toward and away from the side surface of the gap. A spring means is provided for continuously urging the clamp member toward the side surface of the gap. Plate-registering elements are mounted on the clamp member for approximately registering a flexible plate having cooperating plate-registering elements to the clamp member when the clamp member is located in its predetermined plate-receiving position. Means is provided for locating the clamp member in the predetermined plate-receiving position and that means includes an indicator member carried by the screw means and which is rotatable therewith and is located in a predetermined angular position when the clamp member is in its predetermined plate-receiving position. The indicator member provides by means of its position a visual indication that the clamp member is in its predetermined plate-receiving position.

United States Patent 1191 Norton Dec. 3, 1974 1 PLATE CLAMP REGISTERING [73] Assignee: Harris-Intertype Corporation,

Cleveland, Ohio 22 Filed: Oct. 24, 1972 21 Appl. No.: 299,662

52 0.8.0. -101/4151 51 int. Cl -114111/34 [58] Field of Search 101/37s,415.1,24s, 286;

33/115,l16,164,136,l53, 180 R, 181 R, 190 R, 174 TD, 84, 88, 142 G, 165, 166; 74/841, 842; 276/15; 235/120, 127, 106,

l08,1l1,1l2,113,114

[56] References Cited UNITED STATES PATENTS 2,386,214 10/1942 Harrold et a1. l01/4l5.l

2,583,640 1/1952 Faeber 101/365 2,775,935 2/1955 Reinartz et al. 101/248 2,905,086 9/1957 Zahradnik 101/248 3,017,830 9/1960 Penner l01/415.l 3,143,962 10/1962 Dobson et a1... 101/248 3,168,040 2/1965 Norton l0l/4l5.l 3,230,879 8/1963 Worthington... 101/378 3,505,953 12/1967 Germann 101/248 3,515,066 2/1968 Ringe 101/378 3,623,430 1l/197l Lessun 101/365 3,696,743 10/1972 .lohne et a1. 101/365 3,727,550 4/1973 Easoz et a1 101/365 Primary ExaminerRobert E. Pulfrey Assistant ExaminerPaul J. Hirsch [5 7] ABSTRACT A rotatable plate-carrying cylinder has a body member. with a longitudinal gap in the periphery thereof. A plate clamp member is mounted in the gap and extends along a side surface of the gap and is laterally adjustable in opposite directions from a predetermined plate-receiving position spaced from the side surface of the gap toward and away from the side surface of the gap. A rotatable screw means threadedly engageable with the clamp member is rotatable to provide for movement of the clamp member toward and away from the side surface of the gap. A spring means is provided for continuously urging the clamp member toward the side surface of the gap. Plate-registering elements are mounted on the clamp member for ap proximately registering a flexible plate having cooperating plate-registering elements to the clamp member when the clamp member is located in its predetermined plate-receiving position. Means is provided for locating the clamp member in the predetermined plate-receiving position and that means includes an indicator member carried by the screw means and which is rotatable therewith and is located in a predetermined angular position when the clamp member is in its predetermined plate-receiving position. The indicator member provides by means of its position a visual indication that the clamp member is in its predetermined plate-receiving position.

1 Claim, 5 Drawing Figures PATENTL 3'974 3.851.583

SHEET 2!)? 2 PLATE CLAMP REGISTERING MECHANISM This invention relates generally to clamps for flexible printing plates, and in particular to means for rapidly and accurately registering such a plate clamp in an exact predetermined position relative to its cylinder so that a plate properly registered to the clamp will be properly registered to the cylinder and press.

Various systems have been proposed for registering printing plates to printing cylinders. Certain of such systems (preregister systems) include a plate clamp accurately positioned on the printing cylinder and having plate aligning means thereon. In such systems, the plate is accurately constructed so that it cooperates with the aligning means on the plate clamp and is therefore accurately positioned relative to the plate clamp. Accordingly, if the plate clamp is accurately positioned with respect to the cylinder and the printing .plate is accurately positioned with respect to the plate clamp, it follows that the printing plate would be accurately positioned with respect to the cylinder. However, in such systems it was often found necessary to adjust or move the plate clamp relative to the cylinder once the printing plate had been locked thereto. Even the most perfect pre-register systems known to date are subject to occasional problems in that human error may cause an image to be slightly off with respect to the plate or improper plate handling during installation of a plate on a cylinder may cause poor registry. If proper registry is not obtained upon installation, it is normal to move the plate clamp relative to the cylinder to rectify the situation. Movement of the plate clamp from its original accurate position when installing a first printing plate naturally requires that the clamp be restored or reset to that original accurate position relative to the cylinder when the first printing plate is removed therefrom so that the Notron printing plate may be pre-registered to the cylinder. Norton US. Pat. NO. 3,168,040 discloses a plate clamp mechanism which includes provision for restoring'the plate clamp to its accurate original position relative to the cylinder after a printing plate has been removed therefrom. In use, the mechanism disclosed in Norton 115. Pat. No. 3,168,040 has been cumbersome and not completely satisfactory.

The present invention is directed to an improved system and specifically an improvement in the registering mechanism for ensuring such accurate repositioning of the plate clamp. The present invention provides a simplification of the structure disclosed in the Norton patent in that the present system is simple and reliable in use and, additionally, involves fewer parts. Moreover, the present invention provides an indicator which readily indicates to the operator when the plate clamp has been returned to its desired position.

In accordance with the present invention, a rotatable screw member is threadedly engageable with a clamp member so that upon rotation of the screw member in opposite directions, the clamp member moves in a respective corresponding direction. The screw member is provided with an indicator means for readily indicating to the operator that the clamp member is in its predetermined accurate position for use with a pre-register printing plate system. Accordingly, the same screw member which is used to provide for movement of the clamp member in opposite directions is also used to indicate the accurate positioning of the plate clamp relative to the cylinder. This constitutes a substantial improvement over the Norton patent structure as shown in Pat. No. 3,168,040.

The indicator means for indicating that the plate clamp member is in its initial accurate position may take different forms. In one embodiment the indicator includes a first member carried by the clamp member and a second member carried by the screw member and which members have aligning surfaces which lie in the same radial plane relative to the screw member when the clamp member is in its original initial position. When the clamp member is not in its original initial position, the aligning surfaces are offset along the axis of the screw member. This enables the operator to readily visually detect the return of the clamp member to its initial position.

In another embodiment of the present invention, the indicator means comprises an indicator member carried by the threaded screw member and which indicates the angular position of the threaded screw member. When the indicator member is positioned so that it is at a predetermined angular position with respect to the operator, the threaded member and clamp will be positioned in the desired initial plate-receiving position. If the angular position of the indicator member is spaced from the predetermined position, then the operator immediately knows that the clamp member is not in its predetermined plate-receiving position. The operator upon removal of a printing plate from the cylinder can adjust the clamp to the desired plate-receiving position by merely rotating the screw member until the indicator member arrives in a predetermined angular position, indicating to the operator that the clamp member is in its desired plate-receiving position.

In accordance with the present invention, the indicator member in both of the afore-mentioned embodiments is releasably clamped to the threaded screw member and when released may be rotated relative to the screw member for initial setup. Moreover, in both embodiments, the screw member is operable to provide for movement of the clamp member in respective opposite directions from its accurate initial position by merely rotating the screw member in respective opposite directions.

Further advantages and features of the present invention will be apparent to those skilled in the art to which it relates from the following detailed description of preferred embodiments thereof made with reference to the accompanying drawings, in which:

FIG. 1 is a view of a printing press plate cylinder having plate clamps for receiving the leading and trailing edges of a flexible printing plate;

FIG. 2 is an enlarged view of a portion of the printing plate of FIG. 1 illustrating the plate clamp adjusting mechanism embodying the present invention;

FIG. 3 is an end elevational view of the mechanism of FIG. 2;

FIG. 4 is a schematic modified view of another embodiment of the present invention; and

FIG. 5 is a sectional view of the mechanism shown in FIG. 4 taken approximately along the line 55 thereof.

According to the present invention, a plate cylinder 10 is mounted for rotation in side frames of a press (not shown) and carries a leading edge plate clamp mechanism l2 and a trailing edge plate clamp mechanism 13 in gap 11. In the form of the invention illustrated herein, the leading edge plate clamp 12 includes an elongated bar 14 which acts as the lower jaw of the clamp and a plurality of upper jaws 15 which are capable of being independently clamped upon a printing plate 16.

The printing plate 16 is shown in dot-dash lines in FIG. 1 as it is initially inserted between the jaws 14, 15 of the plate clamp 12. When initially inserted, the plate 16 is registered against a round register pin 17 and one side of a square register pin 18. In the form of the register system shown herein it will be seen that the pin 17 is encompassed by the plate on one-half of the circumference, thus providing both front and side registry of the plate while the square pin 18 provides front registry of the plate only, since a notch 19 in the register edge of plate 16 is wider than the portion of the pin 18 engaged thereby. The pins 17 and 18 and their corresponding notches effectively provide what is commonly referred to as a three-point register of the plate 16 to the plate clamp 12. It is to be understood that the plate 16 was previously prepared as a lithographic or relief printing plate of a flexible variety with the image portions thereon being in exact registration with the registered notches on the leading edge of the plate 16. The pins 17 and 18 and the notches with which they cooperate comprise in essence a plate pre-register system. The plate registering elements 17 and 18 which are mounted on the clamp member cooperate with the notches in the plate to approximately register the flexible plate to the clamp member 14 when the clamp member 14 is located in a predetermined platereceiving position. This, in turn, results in the plate 16 being properly registered with respect to the cylinder.

The plate 16, after being held in position by a pressman against the register pins 17 and 18 with jaws 15 open, is clamped by the leading edge plate clamp 12 by actuating each of the jaws 15 to clamp the plate 16 against the bar 14. Jaws 15 are actuated to a locked position by rotation of a longitudinal grooved shaft 20, as is well known. The groove in the shaft, when coinciding with the tail of the jaws l5, enables the jaws to be opened by a spring means (not shown). The jaws 15 are pivoted about round-headed screws 21 in a conventional fashion. When the shaft 20'is actuated to effect clamping of the plate 16, the upper jaws 15 are cammed to pivot about the heads of the screws 21 to grip the plate 16.

Once the leading edge of the plate 16 is gripped by the clamp 12, the cylinder 10 is rotated until the plate 16 is wrapped around the cylinder under pressure from another cylinder. This wrapping takes place until only the trailing edge portion of the plate 16 remains free. The trailing edge of the plate is then tucked into the jaws of the trailing edge plate clamp 13 in similar fashion to the manner in which the leading edge was received by the clamp 12, with the exception that the trailing edge plate clamps l3 ordinarily will not require the use of plate registering means such as the pins 17 and 18. Each trailing edge plate clamp 13 includes an upper jaw 22 and a grooved shaft 23. The grooved shafts 20 and 23 of the clamps 12 and 13, respectively, are rotated by engaging pins in radial holes in enlarged portions 24 of the shafts 20 and 23.

If everything in the plate-making process has been performed accurately from the camera to the press and if all the registering elements are in their exact preset positions, then the plate 16 should be properly located on the cylinder 10 when initially installed so that the printing job may be run without any further adjustment of the plate 16 on the cylinder. While this is ideal, it is not always possible. Any slight error in the processing or mounting of the plate may cause or require some adjustment of either, or both, the leading edge clamp mechanism 12 or the trailing edge clamp mechanism 13 relative to the cylinder 10.

The present invention provides a mechanism for cffecting that adjustment of the clamp mechanisms 12 and 13 and also provides for enabling the clamp mechanism 12 to be returned to its initial or preset position prior to assembly ofa plate on the cylinder 10. In order to make positive movements of the trailing plate clamps, jackscrews 25 are provided which upon rotation cause the clamp mechanism 13 to move within the gap 11, as is conventional. In addition, jackscrews 26 are associated with both the leading and trailing plate clamp mechanisms to enable side adjustments thereof, also as is conventional.

In accordance with the present invention, a simple and reliable mechanism is provided for adjusting the leading edge plate clamp mechanism 12 laterally within the gap 11. The mechanism is generally designated 30. Not only does the mechanism 30 effect the adjustment, it is constructed so that an operator can readily visually determine when the plate clamp mechanism is in its predetermined initial position for receiving a preregistered printing plate.

In the embodiment illustrated in FIGS. 1-3, a plurality of such mechanisms are located at spaced axial locations along the plate clamp mechanism 12. Each mechanism 30 is operable to adjust the section of the clamp mechanism 12 with which it is associated. Each of the mechanism 30 includes a threaded jackscrew threadedly received in a threaded opening 41 in the body or bar 14 of the plate clamp. The head end of the jackscrew 40 is located in the gap 11, and its inner end is engageable with a pin 43. The pin 43 is slidably disposed in the opening 41 in the bar 14 and projects outwardly of the bar 14 and into contact with the side surface 44 defining a portion of the gap 11 in the cylinder 10. Upon rotation of the jackscrew 40 relative to the bar 14, the bar 14 is moved relative to the surface 44 axially of the jackscrew. Pins 45 interconnect the leading and trailing edge plate clamps and springs 46 surround the pins. The springs 46 urge the clamps 12 and 13 toward the sides of the gap 11 and maintain the tips of the pins 43 in contact at all times with the side surface 44 of the gap.

It should be apparent that, as shown in FIG. 2, the bar 14 is spaced slightly from the adjacent side 44 of the body of the cylinder 10. This spacing (labeled A in FIG. 2) enables the jackscrew 40 to be rotated in one direction to allow for movement of the bar 14 toward the side 44 of the cylinder by the springs 46. Likewise, the jackscrew 40 may be rotated in the opposite direction in order to move the bar 14 away from the side 44 of the cylinder in opposition to the springs 46. Therefore, the jackscrew 40 can be rotated in either direction in order to effect a corresponding adjusting movement of the bar 14 with which it is associated.

As noted hereinabove, jackscrew 40 has a specific angular position to which it is set in order to effect positioning of the clamp mechanism 12 in its registered or predetermined plate-receiving position on the cylinder. The position is determined, of course, by the type of pre-registration system and the location of the registering pins 18, 17 on the bar 14.

Associated with the jackscrew 40 is an indicator mechanism for indicating that the jackscrew 40 is in a predetermined position and that therefore the bar 14 is positioned in its predetermined plate-receiving position. This indicator mechanism is designated generally 50 in the drawings.

The indicator mechanism 50 comprises a first indicator member, generally designated 52, and which comprises a block which is secured by a fastener 53 to the body 14 and which moves axially relatively to the jackscrew 40 along with movement of the body 14 axially along the jackscrew 40. A second indicator member 54 is clamped to the jackscrew 40. The member 54 is clamped to the jackscrew by a clamping ring 55 and a plurality, namely, four, of screws 56 which extend through the head 57 of the jackscrew 40 and into tapped openings in the clamp ring 55. The indicator member 54 has a central opening 58 therethrough and the fastening screws 56 extend through that opening into the tapped openings in the clamp ring 55.

This clamping mechanism releasably clamps the indicator member 54 to the jackscrew 40 and, if released, the indicator member 54 may be rotated relatively to the jackscrew 40. This provides the advantage that during assembly or setup of the mechanism 30, the gap A or position of the body 14 relative to the side surface 44 of the cylinder may be set by rotating the jackscrew 40. After the gap A is set to the desired dimension, the indicator member 54 may be rotated to its desired position where a projection 54a thereon is projecting directly toward a projection 52a on the block 52. When so positioned, the screws 56 may then be tightened in order to clamp the indicator member 54 in the position indicated in FIGS. 2 and 3.

After the gap A has been established, a printing plate may be secured on the cylinder and while approximately registered, some adjustment of the printing plate may be necessary which is accomplished by rotation ofjackscrews 40. When such a printing plate is removed from the cylinder 10, the clamp bar 14 and clamp mechanism 12 can be returned to their pedetermined position re-establishing gap A by merely rotating the jackscrew 40 into a position where the indicator members 54, 52 are aligned. The rotation of the jackscrews 40 is effected by a suitable tool which may be engaged in any one of four passages in the head 57 of the jackscrew and then turned.

The aligned position of the members 52, 54 can be readily determined visually by an operator. When in the aligned positions, side surfaces 54b, 52b, respectively, of the indicator members 54, 52 lie in a radial plane (designated X in FIG. 2) relative to the jackscrew 40. In the event that the members 52, 54 are not in axial or radial alignment with respect to the axis of the jackscrew 40, then this is readily visible to an operator of the press, since the operator of the press is looking radially into the cylinder, as illustrated in FIG. 2. If the members 540 and 520 are not in radial alignment, such can be readily determined as when the member 52a may be in a position such as the dotted line position illustrated in FIG. 2. When in such dotted line position, the operator can readily determine that the member 52 is displaced axially of the jackscrew 40 relative to the member 54 (surfaces 52b, 54b are not in radial plane X) and, accordingly, the operator knows that the clamp bar 14 is not in its predetermined position to which it should be set. Also, when members 52, 54 are aligned properly, the space between tips 52a, 54a is minimal. This space is greater than the minimum when the members are not aligned as, for example, when the member 54 has been rotated to the dotted position shown in FIG. 3. When the members 52, 54 are aligned, this is readily visible to the press operator, since the surfaces 52b, 54b lie in plane X and the space between the members is minimal.

As one example, the screw threads on the jackscrew provide for approximately 0.001 inch of adjustment for every 9 of rotation of the jackscrew. This means that a full 360 rotation of jackscrew 40 moves the bar 0.040 inches. Normally, the range of adjustment for purposes of handling any inaccuracies not taken care of by the pre-register system requires only adjustments within the range of approximately 0.005 inch, and most of the adjustments are substantially less than 0.005 inch. Thus, rotation of the jackscrew 40 for in opposite directions takes care of the normal adjustments required.

A modified embodiment of the present invention is illustrated in FIGS. 4 and 5. As illustrated in FIGS. 4 and 5, the jackscrew 40 is provided with a similar type of clamping mechanism as that described in connection with FIGS. l-3 for clamping an indicator member, generally designated 60, thereon. In this case, the indicator member 60 includes a projection which projects radially of the jackscrew 40. The projection 65 has tapered surfaces 65a and 65b thereon which may be painted different colors for a purpose which will be described hereinbelow. When the projection 65 points directly at the operator, namely, directly radially of the jackscrew 40 toward the operator of the press, the operator knows that the plate clamp is positioned in the desired preset or predetermined position. If the indicator 65 is in one direction or the other from that position, as is illustrated in dotted lines in FIG. 5, then the operator knows that the jackscrew 40 is not in the desired preset position. If the threads on the jackscrew are constructed so that the adjustment is not such that would require 360 of rotation of the jackscrew 40 at any time, then the operator would know at all times whether or not the bar 14 and clamp mechanism are in the predetermined desired positions. Of course, this can be accomplished by merely controlling the pitch on the threads on the jackscrew 40 and making that pitch such that for 9 of rotation of the jackscrew, 0.001 inch of movement of the bar 14 results.

The above description relates to the use of the improved plate clamp mechanism for a single printing,

unit. The plate clamp mechanism is, of course, usable in each unit of a multi-color press as well. When so used, the gap A is established in the first unit and the indicator member 54 or 60 is then clamped in proper position. Thereafter, the gap A may be set in the subsequent units by printing test samples and then making appropriate adjustments of the plate clamps as required. After the adjustments are made, the indicator member 54 or 60 can be clamped in proper position to the jackscrew 40, so that the gap A can be reestablished, as above described, if the clamp mechanism is adjusted relative to the cylinder.

In view of the foregoing, it should be clear that applicant has provided a substantial simplification with respect to the mechanism for properly positioning the plate clamp on a printing cylinder for purposes of receiving a pre-registered printing plate thereon, and that the clamp mechanism, even though adjusted from a preset position, may be readily returned to the preset position upon removal of the printing plate for purposes of receiving another plate thereon, and that such is accomplished by provision of a rotatable jackscrew which has a suitable indicator mechanism thereon for indicating the predetermined plate-receiving position of the clamp mechanism which has the preregistering elements thereon.

Having described my invention, I claim:

1. In a rotatable plate-carrying cylinder having a body member and a longitudinal gap in the periphery thereof which gap is defined in part by a side surface of said body member, a plate clamp member mounted in the gap and extending longitudinally along said side surface of the gap and laterally adjustable transversely of the gap in opposite directions from a predetermined plate-receiving position spaced from said side surface of the gap toward and away from said side surface, first means for positively adjusting said clamp member away from said side surface including at least one rotatable screw threadedly engageable with said clamp member and having means associated therewith contacting said side surface so that upon rotation thereof said clamp member moves away from said side surface, second means for continuously urging said clamp member toward said side surface in opposition to said screw, plate-registering elements mounted on said clamp member for approximately registering a flexible plate having cooperating plate-registering elements to the clamp member when it is located in said predetermined plate-receiving position, and means for accurately locating said clamp member in said predetermined position comprising an indicator means carried by said screw and rotatable therewith and located in a predetermined angular position of said screw when said clamp member is in its predetermined plate-receiving position, said screw being rotatable in a first direction from said predetermined position to move the clamp away from the side surface and rotatable from said predetermined position in the opposite direction to permit the second means to move the clamp toward the side surface, said first and opposite directions thus providing movement of said plate and clamp member from approximate registering position as provided by said plate-registering elements transversely of the gap to a final position accurately registering said plate to said cylinder, and said indicator means, upon subsequent removal of said plate and rotation of the screw back to said predetermined position, providing by means of its angular position a visual indication that said clamp member has been accurately restored transversely of the gap to its said original predetermined platereceiving position, adjusting means releasably securing said indicator means to said screw so that when released said indicator means may be angularly moved with respect to said screw and when secured to said screw rotates therewith, said at least one screw member having a threaded stem portion threadedly engaged with said clamp member and a head thereon located within said gap, and said adjusting means including means for releasably clamping said indicator means to said head to locate said indicator means within said gap, said indicator means comprising an indicator member having an opening therethrough, the stem of said screw member extending through said opening,

and said means for releasably clamping said indicator member to said head comprising a clamp ring located on the side of said indicator member opposite the side adjacent said head and fastener means extending through said opening in said indicator member for securing said clamp ring, said indicator member and said head together and when released enabling said indicator member to be angularly moved relative to said screw member, clamp ring and head. 

1. In a rotatable plate-carrying cylinder having a body member and a longitudinal gap in the periphery thereof which gap is defined in part by a side surface of said body member, a plate clamp member mounted in the gap and extending longitudinally along said side surface of the gap and laterally adjustable transversely of the gap in opposite directions from a predetermined plate-receiving position spaced from said side surface of the gap toward and away from said side surface, first means for positively adjusting said clamp member away from said side surface including at least one rotatable screw threadedly engageable with said clamp member and having means associated therewith contacting said side surface so that upon rotation thereof said clamp member moves away from said side surface, second means for continuously urging said clamp member toward said side surface in opposition to said screw, plate-registering elements mounted on said clamp member for approximately registering a flexible plate having cooperating plate-registering elements to the clamp member when it is located in said predetermined plate-receiving position, and means for accurately locating said clamp member in said predetermined position comprising an indicator means carried by said screw and rotatable therewith and located in a predetermined angular position of said screw when said clamp member is in its predetermined platereceiving position, said screw being rotatable in a first direction from said predetermined position to move the clamp away from the side surface and rotatable from said predetermined position in the opposite direction to permit the second means to move the clamp toward the side surface, said first and opposite directions thus providing movement of said plate and clamp member from approximate registering position as provided by said plateregistering elements transversely of the gap to a final position accurately registering said plate to said cylinder, and said indicator means, upon subsequent removal of said plate and rotation of the screw back to said predetermined position, providing by means of its angular position a visual indication that said clamp member has been accurately restored transversely of the gap to its said original predetermined plate-receiving position, adjusting means releasably securing said indicator means to said screw so that when released said indicator means may be angularly moved with respect to said screw and when secured to said screw rotates therewith, said at least one screw member having a threaded stem portion threadedly engaged with said clamp member and a head thereon located within said gap, and said adjusting means including means for releasably clamping said indicator means to said head to locate said indicator means within said gap, said indicator means comprising an indicator member having an opening therethrough, the stem of said screw member extending through said opening, and said means for releasably clamping said indicator member to said head comprising a clamp ring located on the side of said indicator member opposite the side adjacent said head and fastener means extending through said opening in said indicator member for securing said clamp ring, said indicator member and said head together and when released enabling said indicator member to be angularly moved relative to said screw member, clamp ring and head. 